I also get the 500 Internal error on some agents with the "not a Hash" error on the server. This is only happening to the data that some devices are sending to OCSNG version 2.3 server.
I generated a XML file for a problematic PC running the OCSinventory agent to generate XML file on the host.
1. I copied it to my PC and tried to import the XML as it was using the Local Import function. I got the internal 500 error without any data imported.
2. Removed the Software section = <SOFTWARES> from the XML and was still not able to import.
3. Removed all the XML groups after the Software section like VIRTUALMACHINES and SOUNDS. I was then able to import.
4. Returned all the cut info back into the original XML and saved. When importing this file it imports without issue.